Gas turbine engines include various pipes or tubes therein for channeling bleed air, fuel, and oil. Since fuel and oil are flammable, suitable couplings must be provided for joining together the various tubes without leaking thereof. A typical leak-proof coupling includes a pair of mating annular flanges welded to adjoining tube ends with the flanges having a plurality of fastener holes around the circumferences thereof. A suitable annular gasket is disposed between these mating flanges, and fasteners extend through the respective holes for clamping together the two mating flanges and compressing therebetween the gasket for maintaining a leak-proof coupling. These couplings, however, increase the time required during initial assembly and during maintenance since the mating flanges must be properly aligned together and the several fasteners must be installed or removed.
Another type of coupling found in gas turbine engines includes a pair of mating flanges and a V-shaped clamping band having a single, tangential fastener which is suitably tightened for clamping together the two mating flanges of adjoining tube ends. One of the mating flanges typically includes an axially projecting rib which abuts the mating flange and radially below which is disposed a metal seal of various configurations including "C," "V," and "E" shaped configurations. This type of seal is used in bleed air systems which extract relatively hot compressed air from the compressor of the engine and channel it through the engine for various conventional purposes. These seals are not considered leak-proof, but the slight leakage thereof of compressed air does not present the concern associated with the leakage of a flammable fluid such as fuel or oil in the environment of a gas turbine engine. The V-band couplings, however, provide easy assembly and disassembly of the couplings which is desirable for maintenance purposes.